Railway track circuitapparatus



Sept. 28, 1943. e. R. PFLASTERER 2,330,515

RAILWAY TRACK CIRCUIT APPARATUS Filed May 27. 1941 Bi? P; Q A ,7 1a) v 24' 12' @Am 1. 2r 2 I A? 1 g 1/ t [A Him 4/22 [4 42m 59 22: 2

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BY 501w HIT. ATTORNEY Patented Sept. 28, 1943 UNIT D STATES PATENT; OFFICE Y Y GeorgeR. Pflasteren Grcenville, Pa., assignor to The Union Switch and Signal Company, Swiss- I vale, Pa.,- a corporation of Pennsylvania 'Application May 27, 1941, Serial No. 395,402

3 Claims. ((1246-11 3) My invention relates to railway track circuit apparatus, and more particularly 'to'track circuit apparatus for control of trap circuits;

At locations where'a dead section occurs'in otherwise continuous track circuited territory, such as multiple track railroad crossings, a trap circuit arrangement is usedto continue the control established by the train approaching such crossing until the train has fully passed beyond the crossing. v

Accordingly a'featu're of my'inventicnis the provision of novel and-improved track circuit apparatus for railway grade crossing locations.

Again, a feature of my invention is the provision of novel and inexpensive track circuit apparatus for the control of trap circuit arrangements. I i

The above features, as well as other objects and 'advantageswhich will become apparent 'as'the specification progresses, I attain'by' arranging the railway withtwo track "sections which extend in opposite directions from the intersection with another railway, and at least one of which sections has a single insulated joint located at a' preselected point with respect to the intersection. Each section is provided'witha' track circuit. The track circuit for the section in- .In the drawing track circuit apparatus for a trap circuit arrangement is provided for a first cluding the additional singleinsulated jointis j provided with an additional series track relay that is shunted only when that portion of the section between the single insulated jointand the end of the section toward the-intersection is occupied. This series track relay is used in' 00- I joints are used, one placed in a selected one of the rails of each of ."said "sections at a preselected operation with the other track relays of the two 7 point withkrespect to the dead section. The

track circuit for each of these two sections in cludes a series track relay connected around the additional insulated joint. The trap circuit is so controlled by such series track relays and the usual track relays that a predetermined control.

view showing one form of apparatus embodying I my invention when used'at a grade crossing.

one of two intersecting railroads andlwhich app'aratu's permitsa signal of the second railroad to be cleared when the rear of a train on the first railroad passes an additional insulated joint placed in a track section of the first railroad rather than when the train vacates the approach track section as now generally required. Such trap circuit arrangement shortens the delay to, trains of, the second railroad and is particularly useful when relatively long tracksectio-ns are required and'when relatively dense trafiic exists on either or both railroads. I Looking .at the-drawing, a first railroad whose track rails are identified by thereference charactors to and lb is intersected at grade by a second railroad whose'track is identified by the reference character 15. formed by insulated rail joints 2 into track'sectionslT 'and'ZT which are spaced apartby a dead section includingthe intersection of the two roads. Additional insulated rail joints 3 and 3c arelp'laced in rail lbat selected points in sections QT and VI, respectively; and each section IT and 2T is provided with a track circuit, the

track circuit for section lT including a battery tion and a track relay AlTR connected around insulated rail joint 30; and the track .cir'cuit for s'ection2T including a battery .6 connected across the rails at the end adjacent the intersection, a

\ trackrelay 2TR connected across the rails atthe opposite end'of the section and a track relay A2TR connected around insulated rail joint 3'.

Two signalsRZ and L2 ,for the first railroad are located at the remote end of sections Pr and 2T, respectively, -to govern traffic moving over the intersection',"-signa1 R2 'governing eastbound traffic" and signal L2 governing westbound traffic. In' like manner two signals R4 and L4 are located along track IE-of the second railroad to govern traffic in opposite directions over the intersection. These signals may be of any stand- The'rails lit-and lb are ing to standard practice and these signal operating circuits need not be described in detail.

The signal control relays are in turn governed by a trap circuit arrangement associated with track sections IT and 2'1 and by manually operable levers SL2 and SL4, and which levers may be levers of an interlocking machine not shown. Each lever SL2 and SL4 normally occupies a center position N as indicated by solid lines in the drawing, and is movable to either a left position L or a right position R as indicated by dotted lines in the drawing. Each of the levers operates circuit controlling contacts which are shown in the usual conventional manner with each contact having placed thereon the letters N, L or R to indicate the position of the respective lever at which that contact is closed. For example, contact 85 of lever SL2 carries the letters NL to indicate that this contact is closed at both the normal and left positions of the lever.

Two directional stick relays ES and WS are included in the apparatus, relay ES being. associated with eastbound traffic and relay WS with westbound traffic of the first railroad. Relay ES is normally energized over a stick circuit including contact I35 of lever SL2 and its own front contact 87, while relay WS is normally energ zed over a stick circuit including contact 83 of lever SL2 and its own front contact 90. A pick-up circuit for relay ES includes lever contact 85, front contact 86 of track relay ITR and back contacts 9| and 92 of relays A2TR and 2TB, respectively; while a pick-up circuitvfor rela'y WS includes lever contact 88, front contact 89 of relay ZTR and back contacts 94 and ,95 of relays AITR and ITR, respectively. In accordance with standard practice, a normally open contact 93 of a time element device ITE when closed serves to shunt the back contacts 9i and 92in the pick-up circuit of relay ES, and a normally open contact 96 of device 4TE when closed serves to shunt back contacts 94 and 95 in the pick-up circuit of relay WS.

Another stick relay 4S is provided and is controlled over a circuit which can be traced from terminal B through front contacts 91, 98, 99, I00, IBI and I02 of relays ITR, 2TB, AZ'I'R, AITR, ES and WS. respectively, winding of relay 4S and to terminal C. A front contact I03 of relay 48 serves to shunt around contacts I92 and Ifil of the directional relays WS and ES.

Whenan eastbound train is to move through section IT and over the intersection, lever SL2 is moved to its right position R, and a control circuit for signal control relay RZH is vcompleted from terminal B over lever contact I64, front contact I95 of relay 4S, a normally closed contact IIlB of device ITE, lever contact I01 and windin of relay RZH to terminal C, and relay RZH is picked up to close at its frontcontact I2I the operating circuit of signalRZ with the result that that signalis operated to a proceedposition. With lever SL2 moved to its right position'to open contact 85 the stick circuit for directional relay ES is opened and relay ES is released. When the eastbound train advances into section IT, to shunt track relay ITR opening front contact 9! interposed'in the circuit for relay 4S, that relay is deenergized and released causing the circuit for relay RZI-I to be opened so that relay RZH is in turn released with the result that signal R2 is set at its stop position. When the head end of the eastbound train passes'insulated joint 3c, relay AITRis shunted opening .front contact IIlfl to open the circuit for relay 45 at a second point. Signal R2 cannot be again operated for a second train to move over the intersection until relay 48 has been reenergized, that 'is, until directional relay ES is reenergized and and ZTR and the rear of the train subsequently vacates-section IT permitting track relay ITR to pick up.

However, trackrelay A2TR is picked up when the rear of the eastbound train on the first railroad advances over insulated rail joint 3 and .hence the control circuits for relays RAH and L lI-I associated with the second railroad are prepared so that either of these relays can be picked up to clear the respective signals R4 and L4 by a movement oilever SL4. Assuming that as soon as the eastbound train passes beyond insulated joint 3 and relay AZTR picks up, the lever SL4 is moved to its right position R, a circuit is formed from terminal. B overlever contact III], front contacts III, II2,.II3 and H4 of relays AZTR, WS, ES and AI'I'R,,respectively, lever contact I I5, winding of relay R4H andto terminal C, and relay RliH is picked up to close at its front contact I22 an operating circuit for signal R4 with the result that signal R4 is operated to a proceed position to permit a train on track 'IS to move over the intersection. In the case lever SL4 is I moved to its left position L then a circuit is formed from terminal B over lever contact IIS,

. front contacts H4, H3, H2 and III of.relays 'is picked up to .clear signal L2.

AITR, ES, WS and AZTR, respectively, lever contact I I1, winding of relay L4H and to terminal C, and relay L4H is picked up to close at front contact I23 an operating circuit to clear signal L4 to permit a train on track 15 to move over the intersection.

Assuming the apparatus is normal and it is desired to clear signal L2 for a westbound train, the lever SL2 is moved to its left position L where a circuit is formed fromterminal B, overlever contact I08, contact 506 of device ITE, front contact Iii-5 of relay 4S, lever contact I09. winding of relay L2H and to terminal C; and relay L2H When the westbound train enters section 2T, relay ZTR is released opening front contact 98 in the circuit for relay 4S with the result that relay 4S is released vacates section 2T permitting relay 2TB to be picked up. As'soon as the westbound train has cleared the intersection and the rear of the train advances beyond insulated rail joint 3c so that relay AITR is picked up, the circuits for signal control relays R4H and L4H of the secondrailroad are prepared and either signal R4 orwL I can .becleared by an operation of leverSL i to permit a train on track I5 to moveoverthe intersection. It is to be seen, therefore, that with the apparatus of the drawing, the signals R4 and.

L4 of the second railroad can be cleared as soon as the rear of a train on the first railroad passes either insulated joint 3 or 3c depending upon the direction of traffic and that the control established on the first railroad when a train aproaches the intersection is continued until the train passes the dead section at the intersection.

Although I have herein shown and described only one form of railway track circuit apparatus embodying my invention, it is understood. that various changes and modifications may be made therein within the scope of the appended claims without departing from' the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a stretch of first railway intersected at grade by a second railway and formed by insulated rail joints into two track sections one on each side of the intersection, an additional insulated rail joint placed in one rail of each of said track sections at a preselected point with respect to the intersection; a track circuit for each track section and including a current source connected across the rails at the end toward the intersection, a track relay connected across the rails at the other end and another relay connected around the additional insulated joint of the same section; signals for governing traffic in opposite directions over said intersection on said second railway, directional means controlled in part bysaid track relays to a first condition when said track sections are unoccupied and to a second condition when a train on said first railway approaches the intersection and which means is restored to its first condition when such train recedes from the intersec tion, and a control circuit governed by said directional means and by said track relays and said other relays to permit either of said signals to be cleared when a train approaching the intersection on said first railway has passed over the intersection andthe rear of the train has passed beyond the additional insulated joint of the track section through which the train is receding from the intersection.

2. In combination, an east-west railway intersected by a north-south railway and formed by insulated rail joints with an east and a west track section which are separated by a dead section including the intersection, an additional insulated rail joint placed in one rail of each of said track sections at a point preselected with respect to the dead section; a track circuit for each of said track sections and including a current source connected across the rails at the section end adjacent said dead section, a first track relay connected across the rails at the section end remote from the dead section and a second track relay connected to said one railaround the additional tersection, an additional insulated rail joint joint of the respective section; said first and second track relays of each track circuit normally energized and picked up, an eastbound and a Westbound directional relay, each of said directional relays normally energized through a stick circuit including a normally closed contact of a signal governing device and which contact is opened when a train is to approach the intersection on said east-west railway in the direction corresponding to that of the directional relay, a pick-up circuit for each directional relay including a front contact of the first track relay for the track circuit of the corresponding section and a back contact of the first track relay for the trackcircuit of the opposing section, a signal for the north-south railway to govern trafiic over the intersection, and a control circuit including a front contact of each of said directional relays and a front contact of each of said second track relays for governing said signal.

3. In combination, an east-west railway intersected by a north-south railway and formed by insulated rail joints into two track sections separated by a dead section which includes the inplaced in one rail of each of said track sections at a point preselected with respect to the dead section; a track circuit for each of said track sections and including a current source connected across the rails at the section end adjacent said dead section, a first track relay connected across the rails at the section end remote from said dead section and a second track relay connected to said one rail around the additional joint of the same section; said firstv and second track relays of each track circuit normally energized and picked up, an eastbound and a westbound signal to govern trafiic through said track sections, a manually operable means for controlling said signals, an eastbound and a westbound direction al relay; circuit means for each of said directional relays and including contacts of the manually operable means and of each of said first track relays to normally energize that directional relay, to deenergize that relay when the manually operable means is set to clear the associated signal for a train to approach the intersection and to reenergize that relay when such train recedes from the intersection; a signal for the north-south railway to govern trafiic over the intersection, and a control circuit including a front contact of each of said directional relays and a front contact of each of said second track relays for governing the last mentioned signal.

GEORGE R. PFLASTERER. 

